Collating machines are frequently used in line with other paper handling equipment as a means of assembling a plurality of sheets of paper into a particular, desired packet prior to further processing, which may include additional collating, folding and inserting. For further background, reference be made to U.S. Pat. Nos. 2,766,569 and 4,143,981. In a typical paper handling sequence involving an initial output consisting of a plurality of sheets of paper, to be later combined with subsequent output from other sheet feeding devices situated downstream, the initial output is fed from a stack, or a web supply, seriatim to the collator, which collates the output into the desired packets, either in the same or reverse order in which the sheets are fed to the collator. Each packet may then be folded, stitched or subsequently combined with other output from document feeding devices located downstream thereof and ultimately inserted into a mailing envelope.
U.S. Patent Nos. 4,640,506 and 4,805,891 respectively teach the incorporation in the collating machine of removable and moveable reverse order stacking devices for stacking sheets of paper being fed seriatim thereto from a singulating feeder in the same or reverse order as said sheets appear in said singulating feeder.
Generally, the speed of a feeder, which is feeding sheets to a collating machine, is faster than the speed of the collating machine. With known machines, the feeder must stop feeding sheets when a predetermined number of sheets representing a collation have been fed to the collating machine. When the last sheet of the collation is transported to the collation stack in the collating machine, the collator transports the collation to the next station in the paper handling equipment, at which time the feeder begins again to feed sheets for the next collation.
Thus known collators generally reduce the throughput of the paper handling equipment. Because the speed of the feeder is generally faster than a collator, and because the feeder must suspend feeding sheets until the collation accumulated in the collator has been transported from the collator, the feeder is continuously starting and stopping as as it feeds the collator and then waits for a collation to be transported from the collator. This results in additional wear and tear on the feeder mechanical components which is above and beyond the normal wear and tear of a sheet feeder running in a non-stop mode.
Accordingly, the present invention provides a collating machine which eliminates the need for stopping the sheet feeder during normal operation. Additionally, the present invention provides a collating machine which operates at a speed approaching or equal to the speed of the feeder.